Shift control for auxiliary transmissions



May 5, 1953 T. BACKUS v SHIFT CONTROL FOR AUXILIARY Filed Jan. 12, 1951TRANSMISSIONS 5 Sheets-Sheet l THOMAS BACK U5 3nventor WMW / Gttomeg May5, 1953 T. BACKUS 2,637,222

SHIFT CONTROL FOR AUXILIARY TRANSMISSIONS Filed Jan. 12, 1951 5Sheets-Sheet 2 (D In 3am T'H A B ACKU-S May 5, 1953 T. BACKUS SHIFTCONTROL FOR AUXILIARY TRANSMISSIONS Filed Jan. 12, 1951 SSheets-Sheet 5Sumter Tao/was BACKU6 (women Patented May 5, 1953 UNITED STATES PATENTOFFICE SHIFT CQNTROL FOR AUXILIARY TRANSMISSIONS.

Application January 12, 1951, Serial No. 205,751 22 claims. (El. 749-745) This invention relates in general to a device for controlling andeffecting the shift of an auxiliary transmission and more particularlyto a type of device which is dependent for initiation of its operationupon a shift toward neutral of the main transmission with which saidauxiuary transmission is associated.

In the transmission structure disclosed in the application of Ludvigsenand Backus, Serial No. 133,404, there was provided a transmissionarrangement comprising a main gear group, an aux liary gear groupconnected in series with the main gear group having a ratio in its speedchange position substantially equal to theratios included within aselected portion of the main transmission, and semi-automatic means forshifting said auxiliary gear group at the will of the operator butsubject to the limitation that such shifting can take placeonly when themain gear group is in neutral position. Through this arrangement, it ispossible to shift the combinedmain and auxiliary transmissions from lowpo sition to high position, passing twice through the entire range ofsaid selected portion of said main transmission with only onesimultaneous shift of the scars in both gear groups, all as explained indetail in said application.

in the specific embodiment disclosed in said application, a hydraulicmechanism was utilized for actuating the auxiliary gear group. It is thepurpose of this invention to disclose and claim a further structurecapable of carrying out the same broad purposes.

Accordingly, a principal object of this invention is to provide meansfor semi-automatically shifting an auxiliary gear group at the will ofan operator but only when. an associated main gear group is in neutralposition.

A further object of this invention is to pro vide means forsemi-automatically initiating the shift of an auxiliary gear group atthe will of an operator when an associated main gear group is shiftedtoward its neutral position.

further object of this invention is to provide means of the generalnature, as aforesaid, which is accurate and reliable in operation.

further object of this invention is to provide apparatus of the generalnature, as aforesaid, which is sufficiently simple in construction to hefabricated economically and to require a minimum of maintenance.

A further object of the invention is to provide equipment of the generaltype, as aforesaid; which is sufficiently flexible to permit its installation in any conventiona1 type of truck, tractor or similar heavy dutyvehicle.

A further object of. the invention is to provide means of the generalnature, as aforesaid, in which the. point of initiation of shifting ofthe auxiliary gear group with respect to the entry of the main gearsinto neutral may be controlled with a high degree of accuracy.

Other objects and purposes of this invention will become apparent tothose persons acquainted with this type of apparatus upon reference tothe accompanying drawing and the following specification.

In the drawings:

Figure 1 represents a schematic view of appa ratus illustrating andembodyingthe invention.

Figure 2'is a fragmentary view representing a variation from theapparatus illustrated in Figone 11.

Figure 3 is a sectional view of one typical form of transmissionassembly in which my invention may be used, saidsection being taken onthe line III-III of Figure 4.

Figure l is a section of the transmission shown in Figure 3 and taken onthe line IV.-IV of Figure 3.

Figure 5-is a section of the transmission shown in Figures 3 and 4 andtaken on the line V--V of Figure 4.

Construction in generai The structure in general comprises hydraulicallyenergized actuating means for effecting power shifting of the auxiliarygear group and. electrical.- means: controlling said actuating means.

More specifically, the hydraulically energized, or operating, part ofthe device includes a shift fork connected to the auxiliary gear group,a hydraulic cylinder actuating the shift forlna source of fluid underpressure and a. solenoid controlled valve controlling the flow of saidfluid from the source to one end, or to the other end, of the cylinder.The electrical, or control, part of the device includes inseriescircuit,asource of constant potential, the solenoid. controlling thesolenoid controlled valve, a reversing switch forre vcrsing thedirection in which said solenoid, core is urged'and a: plurality of.control switches.

The controlv switches are positioned for actuati'on of each,respectively, by the shift rods of the main gear group, each individualswitch be is not. energized. When the main gear group moves towardneutral position, the open switch is permitted to close and the solenoidis energized. It will then move the valve controlled thereby, or notmove it, depending upon the po sition of the reversing switch, and theflow of pressure fluid is thus directed into one end or the other of thehydraulic cylinder. Thus, upon proper setting of the reversing switch,shifting in the auxiliary gear group is eifected automatically bymovement of the main gear group toward neutral position and theenergization of the means efiecting shifting of said auxiliary geargroup is commenced prior to the attainment of full neutral position bythe main gear group.

Construction in detail In the specific embodiment of the inventionherein disclosed, there is provided a main box l containing a main geargroup, which is associated at one end with an auxiliary box l Icontaining an auxiliary gear group in series connection with said maingear group, and at the other end with an input shaft i connectable withthe clutch of a vehicle (not shown). An output shaft 54 extends from theauxiliary box H for connection to a propeller shaft 96 in a conventionalmanner. Both of said gear groups may be in a single housing (Figures 1and 3) but are here shown in two separate housings for convenience inreference. The auxiliary gear group is provided with synchronizerspreferably of the friction clutch type. The details of both of said geargroups, including said synchronizers, ma be as shown in Figures 3, 4 and5: For the purpose of convenience in description, the terms leftwardlyand ri htwardly, as used in this speci- Y fication, will be understoodto mean leftwardly and rightwardly with respect to the transmissionassembly it when positioned as appearing in Figure 3. The terms inwardlyand outwardly shall be understood to have reference to the geometriccenter of the transmission assembly it or the sections it, ii and i2,thereof. The terms upper or upwardly and lower or downwardly shall beunderstood to refer to the assembly it when positioned and/or operatingin its normal manner of use.

With specific reference now to the main box here selected forillustrative purposes, the main transmission box ie is provided with acentrally disposed main shaft i l and an input shaft I5, which shaftsare preferably coaxial, with their adjacent ends closely spaced fromeach other within the main transmission section it. The main shaft [4 isrotatably supported upon the main bearings it, ltd and [6b within themain box If; and the pilot bearing ll, said pilot bearing being mountedin and upon the adjacent end of the input shaft E5. The input shaft 15is rotatably supported in one end of the main box it by means of themain bearing it. The leftward end of the input shaft is is splined forconventional coupling usually through a clutch with said power means andis supported by a clutch pilot bearing (not shown).

The leftward end of the main shaft 14 is splined for axially movablesupport of the clutch member 23 having leftward and rightward sets ofexternal teeth 2d and 25, respectively. The clutch member 23 is providedwith a circumferential groove 26 between said teeth for engagement by aclutch fork 2?, which fork is actuable by a shift lever 22 in aconventional manner.

The rightward end of the input shaft I5 is provided with an input gear28 having internal and external teeth 29 and 3|, respectively. Theinternal teeth as of the input gear 28 are engageable by the leftwardteeth 24 of the clutch member 23 when said clutch member is in itsleftward position upon the splined portion of the main shaft I l.

A small floating gear 32 which is rotatably supported upon the mainshaft l l adjacent to the clutch member 23, is provided with externalteeth 34 and internal teeth 33 selectively engageable by the rightwardteeth 25 of said clutch member 23.

A medium floating gear 35 is rotatably supported upon the main shaft Madjacent to the rightward side of said floating gear 32 and is providedwith clutch teeth 36. A shaft gear 3'! is positioned adjacent to saidclutch teeth 36. A ring gear 38, having external teeth 39, is providedwith internal teeth 41' whereby said ring gear is supported upon andengaged by the shaft gear 37 and is axially movable leftwardly andrightwardly with respect thereto. The ring gear 38 is provided with acircumferential groove 42 engageable by a clutch fork 43 which clutchfork is I actuable by means of the shift lever 22 in a conventionalmanner.

A large floating gear it, having clutching teeth 45, is rotatablysupported upon the main shaft l4 adjacent to the rightward side of theshaft gear 31.

The rightward end 46 of the main shaft M is splined in a conventionalmanner and extends through the rightward end of the main box l0 into theauxiliary box I I. A second ring gear 47 has an internally splined,centrally disposed, opening for support upon and engagement with thesplined rightward end of the main shaft l4, and is disposed adjacent tothe rightward side of the main bearing [6.

A main output gear as, having external teeth 49, internal teeth 5| andbeing within the auxiliary transmission box I l, is provided with a hub52 which is internally splined for engagement with the rightward end atof the main shaft I4. The main bearings 5a and I6?) encircle the hub 52for support thereof. A pilot bearing 53 is mounted substantially withinthe rightward side of the output gear 48 for rotatable support of theleftward end of the auxiliary main shaft 54 hereinafter described.

A main countershaft 55 is rotatably supported within the main box i9,preferably directly below the main shaft M and parallel therewith, bythe bearings 5E and 56a. A spur gear 51 is secured to the countershaft55 adjacent to the bearing 56 for continuous engagement with theexternal teeth (-3! of the input gear 28. A small spur gear 58 issecured to the countershaft 55 adjacent to the rightward side of saidgear 51. A medium spur gear 59 is secured to the countershaft 55adjacent to the rightward side of the small spur gear 58 for continuousengagement with the external teeth 34 of the small floating gear 32. Alarge spur gear (ii is on the countershaft 55 in continuous engagementwith the medium floating gear 35.

A small countershaft gear 62 is spaced rightwardly from the large spurgear 6| and is continuously engageable with the large floating gear 44.

splinod in a conventional monnen n clutch member to, having acircumferential groove 61, is provided with an internally splined,centrally disposed opening for axially slidable support of the memberupon the splined rightward end of the counterehaft The clutch member 66,which is adjacent to the floating gear t3, has ex ternal teel'i cocacable by the internal teeth 6 of the so dii gear The circumferentialeroove ii engaged by a clutch fork 68 which is actuaroie by the clutchlever 22 in a can ontionel manner, The external teeth 64 of thefloating; gear are continuously ene'aeeable by and with the second ringgear 57.

A idler shaft 53 (Figure 5) is occurre within. the transmission box it,is disposed parallel with the ccuntersliart to, and is pacedsubstantially horizontally therefrom. Since it isprovided withconventional ecarine; and operated in a conventional manner,detailedldcscriptiou thereof is considered unnecessary and is accordinlv omittei The auxiliary boa;

While a wide variety of specific gear structures, includin planetary,may be utilized in the auxiliary box, the hereinafter described con-1struction has been found satisfactory and will be described in detailfor iliu votive purposes. However, whatever specific arrangement isutiliced, it will usually provide two ratios of power transmissionwhichratios diiier by an amount normally equal to the enire range of themain box plus one half 1 Alternatively. however, tlie auxiliary ratiosmay differ by an. mount equal to, or a little greater than, someselected portion of the box go rs.

The auxiliary main shaft {i is disposed Within the auxiliary box l l andis coaxial with the main shaft and a point near its rightward end issupported by the bearing 89. The extreme rightward end of the auxiliaryshaft 5 is spliced in a conventional manner for engagement with apropeller shaft lit by means of any conventional, convenient, coupling9!. A clutcli sleeve 8! is slidably supported upon the auxiliary shaft54 adjacent to the main output gear 58 and is engaged for rotationtherewith by suitable splin- The. clutch sleeve 8i is provided withleftward and rightward rings of external teeth 82 and 83, respectively,adjacent to the axial faces thereof, and a circumferential groove 8d isdimposed intermedii-te the rings of teeth. The aircumferential groove Mis engaged by a clutch fork 35, secured to a semiautomatic shiftingdevice, hereinafter described in detail, for reciprocable movement ofthe clutch sleeve llcn the auxiliary shaft The leftward teeth 62 of theclutch sleeve 8i oontrollably cngageable with the internal teeth ii ofthe main output gear at, such control being effected by thesynchronizing clutch l9 when the clutch sleeve 81 is moved leftwardlyalong the auxiliary main shaft it! An auxiliary output gear at which isrotataloly supported upon the auxiliary main shaft 5% adjacent to therightward side of clutch sleeve 8!, is provided with internal teeth 8'!and external teeth 88f. The ri h'tward ring of teeth 83 on the clutchsleeve 35 is controllably engageable with the internal teeth. is! of theoutput gear 85', said control being effected by the synchronizing clutchto when the clutch sleeve 8! is moved rightwardly along the auxiliarymain. shaft 54.

Its leftward end i supported by the (iii The synchronizing clutches i9and to ma be of any convenient and conventional type, such as the coneclutch disclosed and described in Patent No. 2,468,155. Hence, detaileddescription thereof is omitted here.

It will be understood that the capacity of these synchronizers must besufiicient to eirect synchronization, and consequent completion of theauxiliary shift, during the time the shift lever i passing throughneutral position at a relatively rapid rate, and preferably during the,first half of said passage, having in mind that the entire shift willnormally take about 0.6 second on. pshift and about 1.8 seconds on adownshift. Thus, synchronization and completion or the auxiliary shiftwill preferably be completed in substantially less than the 0.5 secondand to accomplish this the synchronizers must be or reltlvelv largecapacity.

An auxiliary countershaft 82 (Figure 3), which is preferably parallelwith the auxiliary main shaft 5 5 and spaced downwardly therefrom, isrotatably supported at its extremities within the auxiliary box H by thebearings 93 and 93a. A large gear so is supported upon the auxiliarycountorsbaft 92 near its leftward end for rotation therewith andcontinuous engagement with the external teeth to of the main output gear8 A pinion ear 95 is supported upon the auxiliary oountershaft 92 nearits rightward end for rotation therewith and continuous engagement withthe giternal teeth 88 of the auxiliar output gearc Thus in thisembdoiment, the auxiliary box I i is provided with ears efiecting adirect drive nd a reduction gear ratio. The diflerenoe be tween t edirect drive and reduction drive ratios of the auxiliary box in thisembodiment of theinvention is approximately, one half ste greater thanthe entire speed range between first and fourth gear ratios provided inthe main box It.

It will be understood that the above description of the maintransmission box it and auxiliary transmission box 4! is given in detailfor illustrative purposes, only, and it is not intended that thespecific details thereof impose any limitation upon the scope of the,invention.

The main gear group is shifted in a conventional manner by the shiftlever 22 and the auxiliary gear group is shifted in a conventionalmamier by the fork which is secured to the actuating rod Hill of thehydraulic cylinder it. said hydraulic cylinder is actuated by fluidunder pressure from any conventional source We through the conduits, m6.and l l l under the con trol of the valve H32, which valve i 2 of anyconventional type by Which pressure fluid from the source H38 may beintroduced into one end or the other of the cylinder Elli according tothe position of a core bar tit. Said core bar moves in one direction orthe other in response to the polarity of energization of the solenoid 2id. Said solenoid is of any conventional, two-winding, type forcontrolling a two-position valve and each winding is connected through amanually controlled, conventional, reversing switch 2 l 5 into theseries circuit 2:23 which includes the-control switches .256, 21?, 218,259, Qliiaffila, M811, and Zita, and a power source are for energizingsaid solenoid and urgin the core. thereof in one direction or the otheraccording to. the position of the reversing switch Bib. The reversingswitch Zlo may be manually actuated by any conventional means underthedirect control of the operator, such as a lever 22I mechanicallyconnected to saidswitch 2 I 5 by a rod 222, and acts to connect onesolenoid winding or the other to the circuit 223 and to the I powersource 220.

Each of said control switches is preferably a micro-switch of aconventional type and actuated by means such as the plungers 225, 226,227, 228, 225a, 226a, 221a, and 228a, respectively. Said plungers arealigned with the shift rods H4, H5, H6, and III, as shown, for actuationby the respectively adjacent ends of each of said shift rods. Said shiftrods, which are of conventional form, may be as illustrated in somedetail in said application Serial No. 133,404 and as further illustratedin more detail in the United States patent to Padgett, No, 1,943,694.Said shift rods are conveniently supported in the housing I21 of themain box It), as shown in Figure 3. The control switches are alsosupported in said housing I21 and spaced from the respectively Iadjacent ends of the shift rods so that the plun er of each controlswitch will be engaged by the adjacent end of the aligned shift rod onlywhen such shift rod is moved substantially fully to the end of itsstroke and the gear engagement in the main gear group effected therebyis substantially fully accomplished.

Normally, the circuit 223 is closed. Engagement of the plunger of anyone of the control switches by the shift rod associated therewith actsto open the particular switch so engaged, and thus open the circuit 223,thereby stopping the flow of current from the power source 220 throughthe reversing switch M5 to the solenoid 2M. Under these conditions,actuation of the reversing switch 2I5 by the lever 22I will have noimmediate effect upon the solenoid 2M or the valve I02.

In the modification appearing in Figure 2, the micro-switch 246 isoperated by a cam 25! mounted on the side of a shift rod 242. Asappearing in solid lines in Figure 2, the shift rod 2:32 is in itsneutral position. When the shift Mills in its shifted position, as shownby the broken lines in Figure 2, it will actuate the plunger 2 53 ofsaid micro-switch 24B thereby opening said switch and thus open thecircuit 232.

Thus, with the structure shown in Figure 2, the point at which theplunger 243 of a microswitch 246 is released is determined by the lengthof the cam 24-2, whereas by the structure shown in Figure l the contactsof the control switches are broken only when a shift rod issubstantially in its fully shifted position and the contact is closedimmediately after the shift rod starts to move toward its neutralposition.

Operation Although the operation of the shift control, to which thisinvention relates, is apparent from he above description, it will bereviewed in full in the interest of completeness.

The interengagement of the various corresponding gears within thetransmission assembly I 3, for the purpose of effecting the variousabove mentioned gear ratios, may be accomplished in a conventionalmanner by means of the shift lever 22 and the shift rods H4, H5, I I6and I I7. I

The clutch sleeve 8| in the auxiliary box H is moved axially along theauxiliary main shaft 54 (Figure 3) by means of the actuating arm I 00fork 85. When the clutch sleeve BI is in the leftward position itengages the output gear 48, thereby effecting a direct drive through theauxiliary box II. When the clutch gear 8| is in the rightward position(Figure 3), it engages the auxiliary output gear 86, thereby effecting areduction drive through the auxiliary box I I. The synchronizingclutches I9 and BI] provide means for reducing the speed of the mainshaft I4 prior to engagement between the clutch sleeve 8| and the mainoutput gear 48, in a conventional manner, and for speeding up the mainshaft I4 and auxiliary countershaft 92 prior to engagement between theclutch sleeve 8| and the auxiliary output gear 86, also in aconventional manner.

It will now be assumed that the fork 85, when positioned as appearing insolid lines (Figure 1), effects a reduction drive through the gears inthe auxiliary box II and when positioned as appearin in broken lines(Figure 1) it effects a direct drive through said auxiliary box. Thedescription of said operation will commence with the auxiliary geargroup in its lower speed ratio, in which case the lever 22I ispreferably in a downward position, although this is a matter of choice.

With the main gear group, hence the shift rods H4, H5, H6 and III, inneutral position prior to starting the engine (not shown), all of thecontrol switches will be closed thereby energizing the solenoid 2 I4.Such energization effects a positioning of the core bar 2E3 according towhichever winding of the solenoid 2M is energized as determined by theposition of the reversing switch 2I5, so that the valve I82, actuated bythe core bar 2I3, will permit fluid under pressure to flow from thesource I08 through the conduit H36 and the conduit I03 to the leftwardend of the cylinder IIlI (Figure 1). Thus, if the fork is not in itssolid line position (Figure 1) it will be so moved by the actuating armI55.

When a shift is made in the main gear group, one of the control switcheswill be opened by the shift rod concerned, thereby opening the circuit223 and de-energizing the solenoid 2M, but this will have no effect uponthe position of the core bar 2 I 3. Likewise, return of the main box toneutral, which re-energizes the solenoid 2I4, has no effect upon thepositionof the core bar 2I3 since the direction of urging of the corebar 2I3 by the solenoid remains the same. So long as the energizedwinding of the solenoid 2M, which is controlled by the reversing switch2I5, remains the same, the main gear group may be shifted into and outof neutral as often as desired without effecting a movement of the corebar 2I3, and hence no shift of the auxiliary gear group will occur.

However, when it is desired to shift the auxiliary box into directdrive, the lever 22I is manually moved upwardly, thereby reversing theswitch 2I5. If the main gear group is in neutral, the circuit 223 isclosed and the solenoid 2M is accordingly energized. A reversal of theswitch 2I5 effects energization of the other winding of the solenoid 2%,thereby actuating the core bar 2 I 3 which causes the valve I02 tochange the flow of said fluid therethrough. The fluid now flows fromsource I08 through conduit III and conduit let to the rightward end(Figure 1) of the cylinder IIBI, thereby causing the arm IGO- to movethe fork to its broken line position. The auxiliary box is therebyshifted into direct drive.

If the main gear group is in a shifted position when the lever 22l ismoved, and this will be the normal situation, one of the controlswitches is open, thereby preventing flow of current to the solenoid. Assoon as the shift rod which is out of neutral position is moved towardneutral position by the shift lever 22, the control switch being heldopen by said shift rod is permitted to close, thereby closing thecircuit 223 and energizing solenoid Since the switch Bill has beenreversed by upward movement, preselection, of the lever 22!, the otherwinding of the solenoid tilt is now energized and the position of thecore bar 2 i3 is changed, tlnreby causing the valve to change the how offluid to the cylinder it i, which results in a shift of the auxiliarybox in. a manner substantially as described in the preceding paragraph.

The normal time required to complete the shift of the main box intoneutral is absorbed by the normal lag in response of the parts of theauxiliary shifting mechanism, such as the solenoid ti l, valve Hi2 andcylinder on, lhus, even though the circuit 223 is closed immediate- 1:;upon a shift rod startin toward neutral position, the wil complete itsreturn to neutral before the auxiliary box shifts suiilciently to engageits synchronizers.

Where, as may be true in some instances, it becomes desirable to delayslightly the clot g of the circuit 223 to prevent shifting of the an aryher; too early, such delay be controlled to whatever precise extent isrequired by the alternate structure (Figure 2). By proper selection ofthe length of the cam 2 M, it is possible to effect release of theplunger Z43, thereby closing the micro-switch 240, at any desired pointin the travel of the shift rod 242.

It will now be noted that since the main gear group will normally be ingear during operation of the transmission, the circuit 223 will,accordingly, be broken by one of the control switches during themajority of the time and, therefore, the power source 220 will not beunreasonably depleted. When the vehicle with which the transmission isused is not in operation, the cir cult 223 may advantageously be brokenby the ignition key of said vehicle through conventional means (notshown).

Although the above mentioned drawings and description apply to oneparticular, preferred embodiment of my invention, it is not myintention, implied or otherwise, to eliminate other variations ormodifications which do not cepart from the scope of the invention unlessspecifically stated to the contrary in the hereinafter pended claims.

I claim:

1. In a speed transmission for a vehicle. the combination comprising: afirst change speed gear section having an input shaft; a second changespeed gear section, including friction clutch synchronizing meansconnected serially with said first change speed gear section and havingan output shaft; means operable for automatically initiating shifting ofsaid second change gear section upon the commencement of motion in saidfirst change speed gear section from shift position toward neutralposition; and manually operable means for rendering said lastnamed meansoperable or inoperable at the will of an operator.

2. In a change speed transmission for a vehi le, the combinationcomprising: a first change speed gear section having an input shaft; asecond change speed gear section, including friction clutchsynchronizing means, connected serially with said first change speedgear section and having an output shaft; power means for effectingshifting of said second change speed gear section; manually controllablemeans and automatic means serially connected with said manuallycontrollable means, said automatic means being responsive to theposition of the gears in said first section for energizing said powermeans, subject to the will of an operator, upon the commencement ofmotion in said first change speed gear section from a shift positiontoward neutral position.

3. In a change speed transmission a vehicle, the combination comprising:a first change speed section. having an input shaft; a second changespeed gear section, including f iction clutch synchronising means,connected serially with said first change speed gear section and havingan output shaft; shifting means automatically initiating engagement ofsynchronizing means and shifting of second change speed gear sectionupon the commencement of motion in said iirst change speed gear sectionfrom a shift position toward a neutral position, said shifting meansincluding power means effecting engagement of said synchronising meansand shifting of said second change speed gear section; energizing meanseffecting energization of said power means; control means effective tohold said energizing means inoperative so long as the first chan e speedgear section is in any shifted position, said control means beingrendered ineffective upon movement of said first change speed gearsection toward its neutral position and prior to its arrival therein.

i. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having a pair of shaftsand gears thereon providing a plurality of speed ratios; a second changespeed gear section connected in series with said first section andhaving at least two speed ratios, said ratios being spaced apart amountgreater than the spacing of the ratios in said first section; meansincluding a pair of friction clutches associated with said second.section for connecting through a selected ratio in said second sectionto the output of said transmission; pre-selectable means and meansresponsive both to the position of the first section and to one positionof said pro-selectable means for initiating said connecting sufiicientlyprior to the disconnection of the gears of said first section upon theirattaining neutral position that said connecting will take placesubstantially immediately upon the gears of the first section attainingneutral position.

5. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having an input shaft anda second change speed gear section connected serially with said firstchange speed gear section and having an output shaft; electricallyactuated means automatically initiating shifting of said second changespeed gear section upon the commencement of motion in said first changegear section from a shift position toward neutral position, said meansincluding power means effecting shifting of said second change speedgear sec tion upon energization of said power means; means including anelectric circuit effecting energization of said power means; blockingmeans holding said electric circuit open so long as the first changespeed gear section is in any shifted position, and said blocking meansclosing said circuit upon movement of said first change speed gearsection toward its neutral position and prior to its arrival therein.

6. The apparatus described in claim 3 including manually selectablemeans operative when in one selected position to render said shiftingmeans wholly inoperable regardless of the position of said first changespeed gear section.

7. The device defined in claim 5 wherein said blocking means includes anelectrical switch axially aligned with a shift rod of said first changespeed gear section and adapted to be placed in its open position bycontact of the end of the shift rod therewith when said shift rod is inits fully shifted position.

8. The device defined in claim 5 wherein said blocking means includes acam on the side of each of said shift rods adjacent an end thereof and aswitch adjacent the path of movement of each of said rods and openableby said cam when said shift rod is adjacent to, and in, its fullyshifted position.

9. In a main and auxiliary transmission assembly, wherein said maintransmission has a plurality of shift rods associated therewith, a shiftcontrol for the auxiliary part of said assembly comprising incombination: pressure fluid actuated means connected to said auxiliarygear group for shifting same; a source of pressure fluid and a valvecontrolling the flow of pressure fluid in one direction or the other tosaid means; electrically responsive means controlling the position ofsaid valve, and a source of electric power for energizing same; amanually actuatable switch determining the direction of operation ofsaid electrically responsive means and a plurality of normally closedswitches in series between said power source and said electricallyresponsive means; each of said switches being openable by one of saidshift rods as it approaches one end of its normal travel into a shiftedposition.

10. In a shift control for the auxiliary gear group of a transmissionhaving a plurality of shift rods in the main gear group thereof, thecombination comprising: a hydraulic cylinder having an actuating armconnected to said auxiliary gear group for shifting same; a source offluid under pressure, and means including a valve controlling the flowof fluid to said cylinder; a solenoid controlling the position of saidvalve and a source of electric power for energizing same; a switchcontrolling the direction of movement of said valve by said solenoid andmanually actuatable means for reversing said switch; a plurality ofnormally closed switches in series with said power source, said switcheseach being openable by one of said shift rods as it approaches one endof its normal stroke into shifted position.

11. In a main and auxiliary transmission assembly, wherein said maintransmission has a shift lever associated therewith, a shift control forthe auxiliary part of said assembly comprising in combination: pressurefluid actuated means connected to said auxiliary gear group for shiftingsame; a source of pressure fluid and a valve controlling the flow ofpressure fluid in one direction or the other to said means; electricallyresponsive means controlling the position of said valve, and a source ofelectric power for energizing same; a manually actuatable switchdetermining the direction of operation of said electrically responsivemeans and a plurality of normally closed switches in series between saidpower source and said electrically responsive means means responsive tomovement of said shift lever holding one of said normally closedswitches open when, but only when, said shift lever is in asubstantially fully shifted position.

12. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having an input shaft; asecond change speed gear section, including friction clutchsynchronizing means, connected serially with said first change speedgear section and having an output shaft; shifting means automaticallyinitiating engagement of said synchronizing means and effecting shiftingof said second change speed gear section, said shifting means includingpower means effecting engagement of said synchronizing means andshifting of said second change speed gear section; energizing meanseffecting actuation of said power means; control means effective to holdsaid energizing means inoperative so long as the first change speed gearsection is in any shifted position, said control means permitting saidenergizing means to actuate said power means upon movement of said firstchange speed gear section toward its neutral position and prior to itsarrival therein.

13. In a main and auxiliary transmission assembly, wherein said maintransmission has a plurality of shift rods associated therewith, a shiftcontrol for the auxiliary part of said assembly comprising incombination: pressure fluid actuated means connected to said auxiliarygear group for shifting same; a source of pressure fluid and a valvecontrolling the flow of pressure fluid in one direction or the other tosaid means; electrically responsive means controlling the position ofsaid Valve, and a circuit including a source of electric power forenergizing same; a manually actuatable switch in said circuitdetermining the direction of operation of said electrically responsivemeans and further electrically responsive control means in said circuitin series with said electrically responsive operating means and withsaid power source for holding said circuit open Whenever said maintransmission is in a shift position and for permitting said circuit toclose upon the movement of said main transmission toward its neutralposition and prior to its arrival therein.

14. In a main and auxiliary transmission assembly, wherein said maintransmission has a shift control mechanism associated therewith, a shiftcontrol for the auxiliary part of said assembly comprising incombination: pressure fluid actuated means connected to said auxiliarygear group for shifting same; a source of pressure fluid and a valvecontrolling the flow of pressure fluid in one direction or the other tosaid means; electrically responsive operating means for moving saidvalve to a selected position and a circuit including a source ofelectric power for energizing same; a manually actuatable switch in saidcircuit determining the direction of operation of said electricallyresponsive means and a further electrically responsive control means insaid circuit in series with said electrically responsive operating meansand with said power source, said electrically responsive control meanscooperating with said shift control mechanism for holding said circuitopen whenever said main transmission is in a shifted position and forpermitting said circuit to close upon the movement of said maintransmission toward its neutral position and prior to its arrivaltherein.

15. In a multiple speed, heavy duty transmission, the combinationcomprising: a main gear group having a range of gear ratiosapproximately equal to one half the range of the speed ratios in theentire device; an auxiliary gear grou having high and low speedratioswherein the speed differential is approximately equal to the rangeof speed ratios in the main group; and operating means for initiatingshifting of the auxiliary group immediately upon the main groupscommencing movement toward the new tral position; manually controlledpreseleotable means rendering said operating means operable andinoperable at the will of an operat' r; whereby actuation of saidpreselectable means, followed by movement of the main group towardneutral. position, at the end of a shift progression. through the ratiosof the main gears effects an auto-- matic shift of the auxiliary geargroup.

16. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having a pair of shafts,including a main shaft and gears thereon pro-- viding plurality of speedratios; a second change speed gear section connected in series with saidfirst section and having at least two speed ratios, said ratios beingspaced apart an amount greater than the total spacing of the ratios insaidfirst section; means including a pair of friction clutchesassociated with said second section for connecting the input of saidsecond section through a selected ratio in said second section to theoutput of said transmission; preselcctable meansand means responsiveboth to the position of said first section and to one position of saidpreselectable means for initiating said connecting substantiallyimmediately upon the gears of the first section commencing movementtoward neutral position but prior to their arrival in neutral position;whereby during simultaneous, oppositely directioned substantially equalshifts of said first section and said second section, the connection ofsaid shaft to said second sec tion output will utilize the vehicleinertia to affect the speed of rotation of said main shaft in such adirection and to such an extent as to facilitate completion of a shiftin said first section.

17. In a change speed transmission for a vehicle the combinationcomprising: a first change speed gear section having a main shaft and acountershaft and gears thereon providing a plurality of substantiallyequally spaced speed ratios; a second change speed gear section corenected to the output end of, and in series with, said first section andhaving at least two speed ratios, said ratios being spaced apart anamount greater than the spacing of selected ratios in said firstsection; means including a pair of friction clutches associated withsaid second section for connecting said main shaft through a selectedratio in said section to the output of trans mission; means normallyoperable to initiate said connecting immediately upon movement of saidfirst section toward neutral position from any gear ratio position butprior to its arrival in neutral position; manually actuatable meansactuatable independently of the position of said first change speed gearsection for rendering said last named means operable or inoperable;where by during simultaneous oppositely dir-ectioned substantially equalshifts of said first section and said second section, the connection oisaid main shaft to said second section output will utilize the vehicleinertia to affect the speed of rotation of said main shaft in such adirection and to such an extent as to facilitate completion of a shiftin said first section.

18. In a change speed transmission for a vehicle having a propellershaft, the comhinw tion com rising: a first change speed gear sectionhaving a pair of shafts and gears thereon providing a plurality of speedratios; means in cluding a shift lever for shifting the gears in saidfirst change speed gear section; a second change speed gear sectionconnected in series with said first section and having at least twospeed ratios, saidratios being spaced apart an amount greater "than thetotal spacing of the ratios in said first section; normally inoperativemeans inolu ing a pair of riction clutches eiie'ctive when operative forutilizing energy derivable from the vehicle propeller shaft for drivingthe main shaft of said first section and changing the speed or said mains by an amount equal to the range of ratios in the second section and ina direction corresponding to the speed at which said shaft will bedriven in its next shifted position; a pair of independent meansserially arranged, one responsive to the control of an operator and theother actuated immediately as, and each time that, said first changespeed gear section moves from a shifted. position toward its neutralposition and prior to its arrival in neutral position for renderingoperative said normally inoperative means; whereby during simultaneous,oppositely directioned, substantially equal shifts or" said first coolon and said second section, the con ncction of so u main shaft throughsaid pair of friction clutches to the output of said second section willutilize the vehicle inertia to affect the speed of rotation of the mainshaft in such direction and to such an extent as to reduce the effectiveshift required to be made in the first section by an amount equal to theratio difference existing in the second section.

19. In a shift control for the auxiliary gear group of a transmissionhaving a plurality of shift rods in the main gear group thereof, thecombination comprising: a hydraulic cylinder having an actuating armconnected to said auxiliary gear group for shifting same; a source offluid under pressure, and means including a valve controlling the flowof fluid to said cylinder; a solenoid controlling the position of saidvalve and a circuit including a source of electric power for energizingsame; a switch in said circuit controlling the direction of movement ofsaid valve by said solenoid and manually actuatahle means for reversingsaid switch; means cooperating with said shift control mechanism, and inseries with said power source and said solenoid, for opening saidcircuit when said main gear group is in a shifted position and forclosing said circuit When said main gear group commences movement from ashifted position toward neutral position and prior to its arrival in itsneutral position.

20. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having a pair of shaftsand gears thereon providing a plurality of substantially equally spacedspeed ratios; a second change speed gear section connected in serieswith said first section and having at least two speed ratios, saidratios being spaced apart an amount greater than the spacing of aselected portion 01 the ratios in said first section; means including apair of friction clutches associated with said second section forconnecting one of said shafts through a selected ratio in said sec-- endsection to the output of said transmission; manually operable means andmeans responsive both to the position of the first section and to oneposition of said manually operable means for initiating said connectingsufficiently prior to the disconnection of the gears of said firstsection upon their attaining neutral position that said connecting willtake place substantially immediately upon the gears of the first sectionattaining neutral position.

21. In a change speed transmission for a vehicle, the combinationcomprising: a first change speed gear section having an input shaft; asecond change speed gear section including friction clutch synchronizingmeans connected serially with said first change speed gear section andhaving an output shaft; automatically operable means movable intoposition for initiating shifting of said second change speed gear section upon the commencement of motion in said first change speed gearsection from the shift position toward neutral position; and manuallyoperable means serially connected to said automatically operable meansfor permitting or preventing the said operation of said automaticallyoperable means according to the will of an operator.

22. In a main and auxiliary transmission as sembly, wherein said maintransmission has a shift mechanism associated therewith, a shift controlfor the auxiliary part of said assembly comprising in combination:pressure fluid actuated means connected to said auxiliary transmissionfor shifting same; a source of pressure fluid and a i valve controllingthe flow of pressure fluid in one direction or the other to said means,said pressure fluid being at all times applied in said one direction orin said other direction to said means according to the position of saidvalve; electrically responsive means controlling the position of saidvalve, and a source of electric power for energizing same; a manuallyactuatable switch determining the direction of operation of saidelectrically responsive means and an automatically operable switch inseries between said power source and said manually actuatable switch,means cooperating with said shift mechanism for said main transmissionfOr actuating said automatically operable switch upon movement of saidtransmission shift mechanism from a shifted position toward its neutralposition but prior to entry into said neutral position.

THOMAS BACKUS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,866,662 Matthews July 12, 1932 1,916,891 Padgett July 4,1933 1,943,694 Padgett Jan. 16, 1934 2,161,153 Gallum et al. June 6,1939 2,231,966 Swennes et al Feb. 18, 1941 2,365,732 Snow Dec. 26, 19442,445,716 Sternberg July 20, 1948 2,465,885 Koster et a1. Mar. 29, 19492,522,228 Hukill Sept. 12, 1950

